In German, the Nord-Ostsee Kanal. The Kiel Canal is a 98 kilometre waterway linking the North Sea at Brunsbuettel to the Baltic Sea at Kiel-Holtenau. An average of 280 nautical miles is saved by using the Kiel Canal instead of going around Denmark. It is the world's busiest artificial waterway.
The first connection between the North Sea and the Baltic Sea was the Eiderkanal, which used stretches of the Eider river for the link between the two seas. The Eiderkanal was completed in 1784 and was a 43 kilometre part of a 175 kilometre long waterway from Kiel to the Eider mouth at Tönning on the west coast. It was only 29 metres wide with a water depth was 3 metres, which limited the vessels that could transit the canal to 300 tons.
A combination of naval interests -- the German navy wanted to link its bases in the Baltic and the North Sea without sailing around Denmark -- and commercial pressure encouraged the development of a new canal.
In June 1887 the canal was started at Holtenau near Kiel. It took the 9,000 workers eight years to build the Kiel Canal. On June 20 1895 the canal was officially opened by Kaiser Wilhelm II for transitting from Brunsbüttel to Holtenau. A ceremony was held in Holtenau where Wilhelm II laid the final stone and named it Kaiser Wilhelm Kanal.
In order to meet the increasing traffic and the demands of the navy, the canal cross-section was increased between 1907 and 1914. The enlargement projects were completed by the installation of each two larger locks in Brunsbüttel and Holtenau.
After World War I, the Treaty of Versailles internationalized the canal while leaving it under German administration. Adolf Hitler repudiated its international status in 1936. Since the end of World War II the canal returned to being open to all traffic again.